[HN Gopher] A Visualization of Galactic Settlement
       ___________________________________________________________________
        
       A Visualization of Galactic Settlement
        
       Author : the-mitr
       Score  : 163 points
       Date   : 2021-06-16 11:43 UTC (11 hours ago)
        
 (HTM) web link (www.centauri-dreams.org)
 (TXT) w3m dump (www.centauri-dreams.org)
        
       | xwdv wrote:
       | One thing missing from this to help get a sense of scale is a
       | running count of the number of souls populating the galaxy. Would
       | be great if they can also show "settled" population and
       | population in transit to some destination for settlement.
        
       | cletus wrote:
       | A lot of thought has gone into this area. I think the parameters
       | of this simulation are too conservative, which is perhaps the
       | point. Several issues:
       | 
       | 1. Speeds are likely to be much higher. We largely rely on
       | chemical propulsion plus gravity slingshots. For a sufficiently
       | advanced civilization you're likely to concentrate a star's power
       | to provide significant outward propulsion (and braking!) without
       | the mass concerns of carrying reaction mass;
       | 
       | 2. Once you've built one of those starships, it will likely
       | continue on its journey after stopping at a new system to
       | colonize and resupply. It's not clear to me if the simulation
       | assumes this. Given the time frame of 1B years it seems not;
       | 
       | 3. Stars in the Milky Way rotate at different speeds. Like in a
       | few hundred thousand years we'll have a new closest neighbour for
       | awhile. This potentially increases spread as the colonized
       | systems drift further away extending their reach over time;
       | 
       | 4. The simulation just looked like a collection of stars rather
       | than, say, a spiral arm galaxy.
       | 
       | So a realistic timeline is closer to 10M years than 1B years.
       | 
       | I'm firmly in the camp that believes the speed of light is a hard
       | limit. FTL drives and variants (eg wormholes) just seem to be
       | wishful thinking by people who don't understand function domains
       | (eg negative mass). Assuming that, a galaxy-spanning civilization
       | is unlikely to be a civilization in the sense we understand it
       | given that it might take you >1M years to cross from one side to
       | the other.
       | 
       | That's not really a problem for detecting such civilizations as
       | the source of detection isn't likely to be EM transmissions (as
       | the SETI program began looking for). Instead, it's likely to be
       | the IR signatures of Dyson swarms.
       | 
       | Short version: in space, the only way to cool down ultimately is
       | to radiate that heat away into space. That radiation is
       | completely dependent on the temperature of the object radiating
       | heat. For any normal range temperature that's firmly in the IR
       | range. So, if a star has a Dysown Swarm, it'll shine incredibly
       | brightly as an IR source with a very low amount of visible light.
       | 
       | Can you spot one such star? Possibly not. But an entire galaxy?
       | You're likely to be able to see that from 1M+ LY away, easily.
       | 
       | Given the small amount of time this would take to eventuate, in
       | cosmological terms at least, the reason we haven't been able to
       | detect any highly-advanced civilizations within our light cone is
       | quite simple: there aren't any.
        
         | s1artibartfast wrote:
         | #3 was very much included in the simulation
         | 
         | Also, I don't think it was meant to be a fastest or even
         | nominal case simulation. It could clearly be run with different
         | inputs
        
       | rho4 wrote:
       | > one of the comments on the article site: "I have yet to see a
       | convincing argument why advanced civilizations would need to
       | constantly expand like bacteria in a petri dish."
       | 
       | E.g. to escape from violence, conflict and war.
        
         | pfdietz wrote:
         | The assumption there is that advanced civilizations only do
         | things that they "need" to do. That's not true of any
         | civilization at any point in history.
         | 
         | Would an advanced civilization find value in colonization? Very
         | likely -- colonization (biological or machine) is likely the
         | cheapest way to explore another stellar system in detail, with
         | explorers manufactured or born in situ.
        
       | katabasis wrote:
       | The simulation includes this assumption:
       | 
       | > Technology persists in a given settlement for 100 million years
       | before dying out
       | 
       | Seems wildly speculative to me. Our own civilization has only
       | been around for a tiny fraction of that time and future prospects
       | are already looking pretty uncertain. And if we lived in a galaxy
       | where civilizations had this kind of longevity, one would think
       | we'd see some evidence of potential signals out there.
       | 
       | My own pessimistic take on the Fermi Paradox is that life and
       | intelligence may not be very unique but there is no reason for
       | them to be long-lived either. Most civilizations are probably
       | just a "flash in the pan", existing too briefly and separated by
       | too great a distance to ever come into contact with another one
       | (or even learn of another's existence).
        
         | throwaway316943 wrote:
         | My optimistic take is that advanced civilizations capable of
         | travelling the galaxy don't spend their time hanging around
         | planets and stars for the same reason we no longer hang around
         | caves and fire started by lightning. They've mastered fusion
         | and matter transmutation so they just build their own habitats
         | and energy sources wherever they want.
        
       | throwaway316943 wrote:
       | I'm not a fan of galactic settlement simulations mostly because I
       | think they simulate the wrong thing which is rate of diffusion.
       | This treats the civilization as a static thing that simply
       | spreads out at the edges. Compared to the history of human
       | civilizations this is clearly unrealistic. The question to answer
       | is what happens within the already colonized systems over time.
       | How often would breakaway civilizations appear, wars, extinction
       | events, mind upload cults, Luddite revolutions, stagnation, etc.
       | Filters abound. The great civilizations of Earth's past have
       | succumbed to similar fates and we've only progressed by starting
       | over again and again.
        
         | cestith wrote:
         | One thing I seldom see mentioned, too, is why would a K3
         | civilization use easily detected communications like radio or
         | broadly focused light sources? If we launched Voyager 3 (for
         | lack of a better name) next decade, would we use primarily
         | always-on, omnidirectional radio? Would we use a laser? Maybe
         | we'd use a tightly focused, burstable digital radio system.
         | What about next century? Are we simply looking largely for the
         | wrong things?
        
           | grishka wrote:
           | The tightly focused radio beam would still leak into
           | surroundings and scatter off of things, and would thus still
           | be detectable.
           | 
           | Thing is, we still don't know yet what matter and energy
           | actually are. We still don't understand the nature of
           | spacetime. We have a lot of physics to discover. Those other
           | civilizations might have discovered physics in different
           | order. They might be communicating using phenomena we have no
           | idea exist.
           | 
           | It's not right to assume that advanced alien civilizations
           | will be using any technology similar to ours.
        
             | giantrobot wrote:
             | A radio observatory on Earth might be using a fiber optic
             | connection to connect to the rest of the world but it's
             | still looking at natural radio phenomena. It doesn't matter
             | at all what a civilization might use as a backhaul, their
             | Space iPhones could use SubspaceWifi, but their radio
             | observatories will be looking at natural molecular hydrogen
             | emissions.
             | 
             | For an interstellar beacon signal radio is pretty good.
             | Lots of natural phenomena are radio sources, CMB is radio,
             | and a lot of things opaque to visible and near visible
             | light are transparent to radio. So a radio beacon has a
             | good chance of being detected just because any civilization
             | that discovers radio astronomy can stumble across it.
             | 
             | The idea that SETI would ever detect I Love Lqwynngh'tch
             | reruns from an ETI has always been ludicrous. Even our most
             | powerful radio telescopes (by sensitivity) wouldn't be able
             | to detect television or radio broadcasts even a lightyear
             | out from Earth. The only interstellar signal we (or another
             | civilization) will ever detect are very intentional
             | directed signals.
             | 
             | If you had an omnidirectional radio source detectable from
             | interstellar distances you could use it once as it would
             | fry itself and anything around it pretty quickly.
        
         | mordymoop wrote:
         | I feel a need to add an important extra wrinkle. The front line
         | of progress and growth in all things is driven by those who are
         | pursuing progress and growth. If an upload cult arises in a
         | planet, and 90% of the populace retreats into simulations, the
         | remaining 10% are still around and we be selected to be exactly
         | those people most invested in the material universe; within a
         | few years (not millions of years, certainly) there's a good
         | chance they'll be considering expansion. Or, consider how often
         | new civilizations are formed by small populations of refugees
         | from intolerably oppressive larger civilizations. Something
         | like a war, extinction event or ecological difficult is
         | similarly likely to prompt a desire for expansion as it is a
         | total collapse.
         | 
         | Science fiction is full of sentences of the form, "The Klaatu
         | were an alien race who colonized the galaxy a million years ago
         | but have since moved on." I always roll my eyes at this. Almost
         | no matter what the Klaatu are or what they care about, there
         | would be some group of them remaining. And the only Klaatu we
         | would see would be the descendants of the ones who stayed.
         | Giant galactic civilizations made of individuals are unlikely
         | to make coherent collective decisions with no dissenters for
         | the same reason our single planet (with much less serious
         | communications obstacles) never makes unanimous collective
         | decisions.
        
           | Mediterraneo10 wrote:
           | What if 90% of the populace retreats into simulations, but in
           | such a way that the remaining 10% have no political power and
           | no industrial base, because that all remained with the
           | majority? Hard for the non-uploaders to expand in that case.
        
             | varjag wrote:
             | It's hard to command control over the physical reality when
             | you are willingly absent from it.
        
               | autosharp wrote:
               | Is what a chimpanzee might think of the white house.
        
               | z3ncyberpunk wrote:
               | Is what a delusional megalomaniac who out themselves in a
               | matrix might think, just like the president. You
               | seriously have to be a delusional megalomaniac to head
               | the runaway train that is the presidency. Any power
               | gained inside that matrix is disconnected and invalid
               | from any reality and will never be willfully accepted.
               | The only means of control is through perpetual
               | authoritarian violence
        
               | thaumasiotes wrote:
               | I don't understand your argument. How much control do you
               | think the White House exercises over chimpanzees? Your
               | hypothetical chimpanzee is completely correct.
        
               | varjag wrote:
               | Or what rest of the world been thinking of the White
               | House.
               | 
               | Point stands.
        
               | Swenrekcah wrote:
               | POTUS himself may be absent from Africa but not from
               | physical reality, and the physically real resources under
               | their command certainly aren't absent from the various
               | corners of the world.
        
             | sidlls wrote:
             | That's quite contrived in my opinion. How can people
             | uploaded into a simulation maintain that level of control
             | in the physical world for any durable period?
        
               | hyperpallium2 wrote:
               | Software eats the world; control the software.
               | 
               | It's an interesting question. How do people maintain
               | control now? In general, it is not through physical
               | control. We have institutions, we have "manufacturing
               | consent".
        
               | TheOtherHobbes wrote:
               | We have those in a negative sense. Manufactured consent
               | is mostly about directing motivation towards wars of
               | control and acquisition and _preventing other activities_
               | - including the peaceful development of sustainable
               | energy, which is finally happening fifty years after it
               | could have, and non-corporate non-military access to
               | space on top of a non-corporate internet, neither of
               | which are happening at all.
               | 
               | Manufacturing positive consent for a billion-year project
               | is - obviously - a completely different kind of problem.
        
               | Mediterraneo10 wrote:
               | They have to keep up all the computing infrastructure
               | running the simulation, and deal with long-term threats
               | like geological activity and asteroids. That requires
               | having and maintaining considerable technology out in the
               | real world, and if only a mere 10% refuse to enter the
               | simulation, then that minority may not get to benefit
               | from spacefaring technology, or have the capital or
               | industrial base to develop their own.
               | 
               | In fact, since spacefaring presents a threat (kinetic
               | bombardment) to any planetary-bound species, then that
               | majority who choose to enter the simulation may want to
               | expressly prevent the minority from leaving the planet.
        
               | z3ncyberpunk wrote:
               | That's their problem, those who did not Matrix themselves
               | are not beholden to those who gave away their lives
               | without force, but since they are virtual, they have none
               | and exist where the 10% can pull their plug at any time.
               | You out too much faith in virtual existence
        
               | DocTomoe wrote:
               | Wouldn't it be a lot easier for the non-uploaders to, you
               | know, just pull the plug? Or change the input to the
               | digital existances in a way to simulate a reality
               | "outside"?
        
               | Mediterraneo10 wrote:
               | No, because - as I mentioned above - the uploaders would
               | still maintaining all kinds of technology to monitor and
               | control the outside world in order to ward off any
               | threats (natural disasters, sabotage from the non-
               | uploaders) to the computing infrastructure on which the
               | simulations are running. If the majority of society
               | chooses to upload, then that suggests that such
               | protective infrastructure is already so stable and
               | advanced, that the non-uploaders would be powerless to
               | simply "pull the plug".
        
               | philistine wrote:
               | You're getting very close to ending up with the script to
               | The Matrix.
        
               | mordymoop wrote:
               | This is obviously not impossible, but we are now in the
               | realm of adding clauses to an already rather specific
               | scenario, each clause adding another degree of
               | improbability. (The odds of "an upload cult arises on a
               | planet" is by definition greater than "an upload cult
               | arises on a planet AND actively presents anybody else on
               | the planet from ever leaving.)
               | 
               | I think the metaphor to look to isn't necessarily even
               | human civilizations spreading around the globe; it's life
               | spreading through the planet to colonize every niche out
               | of which the slightest scrap of energy can be extracted.
        
           | throwaway316943 wrote:
           | Change the "upload filter" to "total upload filter" smaller
           | chance but still relevant. Also it was a silly sci-fi
           | example, I'm sure sufficiently advanced societies can think
           | up better forms of planetary dead ends.
        
         | belter wrote:
         | Your comment is interesting, but thinking about it, this is the
         | most likely thing to happen:
         | 
         | Any technological advance in interplanetary travel speed or new
         | technologies of renewable and easy source of energy, would
         | promote expansion. The new arrivals to an empty planet could
         | start all over again, claim the resources as theirs, organize
         | their own laws. And if they are overcome somehow move to other
         | planets and start all over again...I think there is wave coming
         | our way if we think about it.
        
           | throwaway316943 wrote:
           | Yes my point is that each system colonized becomes its own
           | independent case subject to destroying itself or regressing
           | or becoming antagonistic towards its parent civilization.
           | Think back pressure or resistance. The question I'm asking is
           | at what point does that resistance turn the tide of
           | expansion.
        
         | scotty79 wrote:
         | they assume 1 successful colonization ship per 100k years. This
         | might take into account periods of stagnation and Luddite
         | revolutions and such. Sentient beings do various weird thing
         | but they do them fairly quickly.
        
           | throwaway316943 wrote:
           | I'm taking issue with the lifetime of the civilization, not
           | the rate at which they send out colony ships.
        
         | godelski wrote:
         | This is far more complex to model, and near impossible to. I
         | wouldn't expect to see this anytime soon.
         | 
         | But to give you some hints, breakaway civilizations would
         | likely happen all the time. Every space program has issues with
         | astronauts not following orders simply because the astronauts
         | internalize the idea of "what are they going to do? Come get
         | me?" This is frequently talked about in settings where they are
         | discussing Moon and Mars colonization. A Martian colony won't
         | really belong to the US/China/EU/whatever for very long. I'd
         | expect something very similar to Red Mars/The Expanse.
         | 
         | Another big reason for this will simply be time of light
         | communication delays. Between Earth and Mars that's 8-15
         | minutes one way. It is highly impractical to control a
         | territory when communication takes so long, they will
         | effectively become independent. We've seen this historically
         | too. Colonies operate drastically differently than their home
         | countries. Being so far away it is difficult to communicate and
         | cultures will diverge, especially considering that their day to
         | day lives will be drastically different. Different needs
         | creates different cultures. But luckily this distance also
         | makes war difficult between two planets. You have months to
         | respond.
        
           | thaumasiotes wrote:
           | > Every space program has issues with astronauts not
           | following orders simply because the astronauts internalize
           | the idea of "what are they going to do? Come get me?"
           | 
           | From the script to _Casino_ :
           | 
           | > Every couple of weeks I used to send Marino back to the
           | bosses with a piece of what I made.
           | 
           | > Not a big piece, but fuck them, what did they know? They
           | were fifteen hundred miles away... and I don't know anybody
           | who can see that far.
           | 
           | On the other hand...
           | 
           | > Between Earth and Mars that's 8-15 minutes one way. It is
           | highly impractical to control a territory when communication
           | takes so long, they will effectively become independent.
           | 
           | This is totally wrong. Between Earth and Earth, empires have
           | exerted effective territorial control while communication one
           | way took _weeks_. A 15 minute delay in communication is
           | meaningless. The problem is the difficulty of traveling, not
           | of communicating.
        
             | pdonis wrote:
             | _> empires have exerted effective territorial control while
             | communication one way took weeks._
             | 
             | That's because the effective territorial control was _not_
             | exercised by the central government of the empire, but by
             | territorial governments that were on the spot and that had
             | pretty much complete authority to act on their own
             | initiative without getting permission from the central
             | government. They only had to meet very general policy
             | goals. So the speed of communication with the central
             | government was not relevant to the effectiveness of the
             | territorial control.
             | 
             | The question is whether a territorial government on, say,
             | Mars would have the same loyalty to the central government
             | on Earth that, say, British territorial governors had to
             | the British empire. Without that loyalty on the part of the
             | territorial governments that are on the spot, there is in
             | fact no way for the central government to effectively
             | control territories.
        
               | godelski wrote:
               | Thank you, this is what I was trying to suggest. That
               | these localized governments, while loyal to their
               | empires, operated fairly independently (which should be
               | fairly obvious for similar reasons to space. Which travel
               | times are actually similar). Hopefully your comment has
               | helped clear some confusion up.
        
               | pydry wrote:
               | Most of the same tactics used to control colonies could
               | be used to control Mars.
               | 
               | Moreover, Mars would probably be utterly dependent on
               | earth for multiple generations.
        
               | pdonis wrote:
               | _> Most of the same tactics used to control colonies
               | could be used to control Mars._
               | 
               | Those tactics only work when backed up by a credible
               | threat of overwhelming force. I do not think the Earth
               | will be in a position to bring overwhelming force to bear
               | on a Mars colony. It's a lot harder to do that across
               | tens of millions of miles of space than it is to do it
               | across an ocean. And even across oceans on Earth it often
               | doesn't work.
               | 
               |  _> Mars would probably be utterly dependent on earth for
               | multiple generations._
               | 
               | I'm not so sure. We have barely even started exploring
               | Mars; we have no idea what resources exist there. We are
               | still discovering new resources here on Earth; I would
               | expect that humans on Mars would be doing the same there.
        
               | edgyquant wrote:
               | True but the reason these territories respected the
               | metropoles laws is because they were aware if they didn't
               | the metropole had the resources to overrun them if they
               | were upset enough. The same will be true of any off world
               | colony for the foreseeable future.
        
               | pdonis wrote:
               | _> the reason these territories respected the metropoles
               | laws is because they were aware if they didn't the
               | metropole had the resources to overrun them if they were
               | upset enough_
               | 
               | I don't think that's true, since, as godelski points out,
               | in a salient historical case where the colonies did _not_
               | respect the home empire 's laws--the United States of
               | America--the home empire did _not_ have the resources to
               | overrun them. The British ended up learning similar
               | lessons in South Africa and India later on.
               | 
               | I think the main reason colonial governments respected
               | the home empire's laws is that the territorial governors
               | and their personnel were loyal to the empire; they
               | believed in the empire and its aims. When that loyalty
               | goes away, as it did in the USA, the home empire can't do
               | much about it.
               | 
               |  _> The same will be true of any off world colony for the
               | foreseeable future._
               | 
               | You must be joking. If the British empire was unable to
               | enforce its will on the United States, with only an ocean
               | separating them, how could an Earth empire possibly
               | enforce its will on a Mars colony, with tens of millions
               | of miles of space separating them?
        
               | godelski wrote:
               | I'm not convinced that's true. The New World exists for
               | exactly this reason. The British were not able to sustain
               | a war half a globe away with the Americans. It is
               | incredibly expensive (hell, even the French supporting
               | the US took a big hit). All a Martian colony would need
               | to do is play guerilla warfare and wait it out. There's
               | plenty of history to suggest that this is an effective
               | strategy.
        
         | narag wrote:
         | There's a factor that would make a difference, a question of
         | identity. A civilization grown out of a migration and only
         | possible thanks to advanced science would look at some things
         | unlike any other that we know.
        
         | xbar wrote:
         | There are lots of questions to answer. Some can be modeled more
         | easily than others. This one is pleasant because the model is
         | simple enough for a broad audience to reason about, and the
         | visualization is straightforward.
        
         | JackFr wrote:
         | It's true that filters abound but the idea that we've had to
         | start all over again is Whig history. It's been a continuum.
         | 
         | That being said I agree with your main point. The difference in
         | worldview, ethics, where man sees himself in the universe over
         | the course of our history (let alone pre-history) has taken
         | dramatic and difficult to model changes.
         | 
         | Imagine the worldview of the builders of the Great Pyramid vis
         | a vis our own. (And then remember that Cleopatra was far closer
         | in time to us than them.)
        
           | QuesnayJr wrote:
           | Isn't it the opposite of Whig history? I thought Whig history
           | was the idea of continual progress.
        
             | throwaway316943 wrote:
             | Yes, thank you, that's essentially what I'm arguing
             | against. There's no reason galactic civilizations should
             | continually progress especially when each settled system is
             | effectively cut off from its parent by light years of
             | distance.
        
         | shusaku wrote:
         | The history of human civilizations is a blink in the eye
         | compared to the history of the human race. And compared to the
         | time scales of the simulations they run. So I wonder if maybe
         | those filters end up as noise when we're talking about filling
         | the galaxy. History is less of a detailed story and more of a
         | fundamental force.
        
       | h2odragon wrote:
       | "looking for technosignatures" .. Which'd be what? AM radio
       | transmissions? Spread spectrum stuff? How would we have
       | interpreted our own "technosignature" 100 years ago?
       | 
       | Compare the efforts it takes to talk to Voyager vs SETI: unless
       | the aliens are talking to us _in the way we are looking for_ we
       | 're not likely to see them.
       | 
       | I won't even get in to the blithe assumptions about the ease of
       | interstellar travel; Charlie Stross has a lot to say there and
       | all said better than I could.
        
         | unnouinceput wrote:
         | You can safely assume that one of the fundamental forces of our
         | Universe is the same, namely electromagnetism, which means that
         | yeah! AM/FM radio would be among those signatures.
        
           | h2odragon wrote:
           | Let me try to express that better: When we were just figuring
           | out FM radio ourselves, i don't think we'd have been capable
           | of recognizing a modern spread spectrum WiFi transmission as
           | a signal. It would have been an elevated noise level and
           | puzzling, perhaps.
           | 
           | So the next hundred years of human advance, I expect, will
           | bring similarly transformative changes in the ways we
           | communicate and the shape of our "technosignature".
           | 
           | Our expectations for what other species might be doing don't
           | seem to be informed by the things we know we've done.
        
             | gus_massa wrote:
             | I can't find an official source, but the graph in this page
             | look interesting https://nutsaboutnets.com/wifisurveyor/
             | 
             | It looks like using only old technology we can detect the
             | signal and identify it as a artificial signal, but it would
             | be very hard / impossible to decode.
        
             | angus-prune wrote:
             | Related to this.
             | 
             | We are basing what we consider natural phenomena on our
             | observations of the galaxy.
             | 
             | If we were to flip the assumption from life being rare to
             | life being pervasive, what assumed natural phenomena could
             | in fact be evidence of life?
             | 
             | There is precedent for this on Earth. We are just startign
             | to discover how much The Amazon rainforest is actually a
             | human creation and basically a massive multi-generational
             | bioengineering project.
             | 
             | This is not a serious position fo mine, btw, I know that we
             | can track most astronomical phenomena back to fundamental
             | laws of nature.
             | 
             | But equally there are some massive astronomical myseteries
             | (dark matter/energy, certain stars being more/less common
             | than expected etc) and I can't quite dismiss the wonder
             | that our baseline assumptions have been tainted by this
             | assumption.
        
               | varjag wrote:
               | Imagine if all the dark matter is repurposed for mega-
               | civilization habitation and energy needs, and the matter
               | we see is poorly suitable rejects
               | 
               | There's your Fermi paradox, we live in a dumpster pile.
        
               | shakezula wrote:
               | I like this interpretation of the Fermi paradox the most:
               | We're a dumpster-dwelling species barely qualifying as
               | sentient compared to the species whose dump we inhabit.
               | 
               | Lines up great with my self-esteem.
        
               | thereddaikon wrote:
               | Or Galaxies are the ultimate mega structure and dark
               | matter is merely the observable signature of the gravity
               | modification tech they use to hold them together.
        
             | unnouinceput wrote:
             | You can listen to all the radio frequencies at once, from
             | low AM ones up to dozens of GHz using inexpensive radio
             | components - it's how bug hunters you see in movies work,
             | they just measure electromagnetic waves, regardless of
             | their wave length.
             | 
             | Granted, you'll not be able to differentiate between them,
             | only that they exists. And at this point of searching for
             | those signatures that's all you need though. Also Marconi
             | was listening to lightning strikes generating radio waves
             | using his radio, and that was over a century ago. Lightning
             | strike generates radio waves all over the spectrum, so we
             | had this capability right from beginning.
        
             | scotty79 wrote:
             | Or in next 100 years we might figure out how to use
             | neutrinos for communication and find out that galaxy is
             | actually quite busy place, it's just nobody uses
             | electromagnetic waves for comms same way they don't use
             | smoke signals.
        
         | s1artibartfast wrote:
         | One of the current technosignatures are em radiation indicating
         | Dyson spheres or swarms around sun's. Another is molecules in
         | planetary atmospheres which are only known to arise from
         | industrial applications.
        
         | [deleted]
        
         | Cthulhu_ wrote:
         | We can capture all known forms of interstellar radiation, we
         | have a baseline of background noise, and we can see if they are
         | chaotic or structured. I don't believe technosignatures are
         | indistinguishable from noise.
         | 
         | I mean sure, sci fi mode engaged, aliens may have ascended our
         | own physics and may use quantum entanglement or subspace for
         | communications and the like, in which case we wouldn't know.
         | And our own signals too will get weaker and garbled over time;
         | I'm not sure if even our own radio broadcasts 100 light years
         | away are discernible from the background radiation of all the
         | stars.
        
       | lapp0 wrote:
       | centauri-dreams.org ... Hmm, more like pipe-dreams.org
        
       | marcus_holmes wrote:
       | Colour me a little disappointed.
       | 
       | Firstly, this seems obvious. The conclusion of "even really slow
       | spaceships will colonise the galaxy given enough time" is almost
       | mind-numbingly banal.
       | 
       | Secondly, the parameters seem to be chosen in order to produce an
       | "interesting" propagation pattern, rather than based on any
       | actual data or guesstimates (I know there is no data, but making
       | shit up is no substitute).
       | 
       | Thirdly, it doesn't answer the big important question of "where
       | are they?" (as fnord77 asks). Saying "even really slow spaceships
       | will colonise the galaxy given enough time" brings us immediately
       | right back to "how much is enough time to colonise the entire
       | galaxy?" which they then say is ~1 billion years.
       | 
       | Fourthly, but they're not here. So the answer to that question
       | must be "over ~10 billion years". So either the simulation is
       | wrong (because it takes longer than ~1 billion years) or it's
       | pointless (because the only other explanation is that there has
       | been no such colonisation effort, so why are we modelling it?).
       | This wasn't addressed at all.
       | 
       | Fifthly, this assumes that all solar systems can be colonised,
       | and will produce another colony ship 100,000 years later (for
       | inadequately explained reasons). Given that we know a fair bit
       | about the actual galaxy (though the simulation doesn't look
       | anything like our actual galaxy), why didn't they run the
       | simulation on our actual galaxy, and exclude the stars that we
       | know can't be colonised (because red giant, etc)?
       | 
       | Finally. Is this the state of cutting-edge research on SETI? This
       | wishful-thinking make-believe "look what I made Mum!" stuff? If
       | this was a bootcamp dev showing off their WebGL modelling demo,
       | I'd be impressed. 'nuff said. Sorry to be harsh, but... really?
       | this is it?
        
         | [deleted]
        
         | avaldes wrote:
         | > Finally. Is this the state of cutting-edge research on SETI?
         | This wishful-thinking make-believe "look what I made Mum!"
         | stuff? If this was a bootcamp dev showing off their WebGL
         | modelling demo, I'd be impressed. 'nuff said. Sorry to be
         | harsh, but... really? this is it?
         | 
         | I mean, when all you have to work is literally nothing all you
         | can do is speculate. It is disappointing but what can they do
         | but throw everything at the wall and see if it sticks.
        
           | throwaway316943 wrote:
           | Well they don't have absolutely nothing. We know how much it
           | costs to get mass into orbit, we know the launch cadence
           | we're capable of, we know how long it takes to build huge
           | vessels like nuclear powered submarines and aircraft
           | carriers, we have realistic proposals for propulsion
           | techniques that could get us to our nearest neighbour. You
           | could make limited extrapolations from these points to figure
           | out how much it would cost and how long it would take to
           | build a colony ship. That would tell you a bit about the
           | conditions necessary to begin colonizing the galaxy and you'd
           | be able to tell if those conditions were likely to occur in
           | the near future. We know how long it took to colonize the
           | Americas so you could adjust that data. That should give you
           | both the rate at which you can create colony ships and how
           | long it takes for a colony to reach the point that it can
           | begin building them.
        
             | s1artibartfast wrote:
             | It seems like this is an entirely different question than
             | the one evaluated in the article.
             | 
             | IT is a an interesting question, but it seems weird to
             | fault the article for not being something different.
             | 
             | Alternatively, one could argue that all of this data is
             | worthless in predicting the industrial capacity of
             | spacefaring culture, at least 100,000 years more advanced.
             | Im guessing this is why they didn't bother.
        
             | marcus_holmes wrote:
             | this. But I see no attempt to do any of this work. Just "1
             | colony ship every 100,000 years, limited to 15 light years"
        
       | unnouinceput wrote:
       | Looking at the video, and assuming that indeed that's how a Type
       | II->Type III civilization spreads around, I've counted 2 full
       | rotations of the original star. One rotation in our galaxy takes
       | 230 million years (https://en.wikipedia.org/wiki/Galactic_year)
       | which means even if we start today to spread around would still
       | take half a billion years to populate the galaxy. Now if only
       | genetics would deal away with aging to be around when that
       | happens :).
        
       | aj7 wrote:
       | It seems like it would be trivial for a civilization to have a
       | policy of no electromagnetic emissions so no signature at all.
       | 10km/second is absurdly slow. Who would want to make the trip,
       | and condemn thousands of generations of her progeny to bizarre
       | ship life and culture?
        
         | douglaswlance wrote:
         | You could load a ship up with frozen embryos and have an
         | automated system that raises the first generation.
         | 
         | Though, honestly, humans are terrible galactic conquerors. The
         | artificial life that we create will be the ones taking over the
         | galaxy.
        
           | hungryforcodes wrote:
           | To be fair, we'd need to have an actual galactic history as a
           | race to know if that's true.
        
           | Syzygies wrote:
           | > The artificial life that we create will be the ones taking
           | over the galaxy.
           | 
           | Exactly. A galactic version of "core wars". If we leave any
           | trace at all it will be our machines. Future life will
           | resemble 3D printers in search of raw materials, not GI
           | tracts in search of food, spores that will survive billion
           | year voyages with infinitesimal chances of success.
        
           | TOGoS wrote:
           | That's the premise of one of my favorite sci-fi stories, The
           | Songs of Distant Earth by Arthur C Clarke. The stuff about
           | what-do-people-do-when-the-apocalypse-is-coming-but-kind-of-
           | a-ways-off was cool too.
           | 
           | (in case anyone scrolling by is looking for additions to
           | their to-read list)
        
             | weeblewobble wrote:
             | also a major plot in Elysium Fire by Alastair Reynolds
        
         | spywaregorilla wrote:
         | Ship life would probably be better than the lives many people
         | experience today, in first world countries. There's also
         | probably some super advanced VR by that time.
        
         | keiferski wrote:
         | Imagine that VR develops over the next few centuries. Millions
         | of people engaged everyday, for 10-12-15 hours. At that point,
         | what's the difference between being on a ship or being on
         | Earth?
        
           | nicoburns wrote:
           | If life is like that, then why bother going?
        
             | m4rtink wrote:
             | To build a Dyson sphere so that you have enough power to
             | finally run VR Minecraft at 60 FPS! ;-)
        
             | spywaregorilla wrote:
             | Because someone wants to
        
             | rho4 wrote:
             | e.g. because your star is about to blow up.
        
             | keiferski wrote:
             | I didn't say I was going to sign up :)
             | 
             | But I don't think it's too far fetched. Imagine a VR system
             | that doesn't require wearing a helmet and can be displayed
             | in physical space. And/or a Matrix-style direct jack into
             | the brain. Any environment you can think of, easily
             | accessible. Doesn't seem that bad to me.
             | 
             | Beyond that, A lot of people already spend 10+ hours
             | staring at screens here on Earth...
        
               | nicoburns wrote:
               | Does it replicate smells, tastes and touch sensations as
               | well as just sound and vision? I spend a lot of time
               | staring at a screen, but it's the time I spend not
               | staring at a screen and interacting with other beings
               | that makes life worth living.
        
               | keiferski wrote:
               | Obviously we are speculating here, but projecting current
               | tech 300-400 years into the future, it doesn't seem that
               | absurd to me.
               | 
               | And don't forget that you'd be in space with tons of
               | other colonists too.
        
             | scotty79 wrote:
             | Why bother staying? Why bother anything? Because why not.
        
           | Cthulhu_ wrote:
           | The ability to get off and out. In practice this is already
           | possible and many people's daily life.
        
         | tomp wrote:
         | All transmissions that are distinguishable from noise are
         | energy loss.
         | 
         | If the ships are big enough, living on them approximates living
         | on a continent / planet...
        
         | s1artibartfast wrote:
         | Who is to say life on a colony ship is undesirable? It could
         | offer the best lifestyle possible and be culturally glorified.
        
         | kingsuper20 wrote:
         | A machine intelligence. Just turn yourself off for the trip.
         | 
         | Generally I'd say that the notion of a Von Neumann machine is
         | so obvious and so effective that there's something really wrong
         | in our guesses on how widespread intelligence is.
        
         | signal11 wrote:
         | > Who
         | 
         | Civilizations aware of imminent extinction-level events may
         | choose to do that, similar to how shipwrecked sailors may
         | fashion a raft and "risk it" in the off-chance they survive.
        
           | edgyquant wrote:
           | But why would they go off to a different system instead of
           | just colonizing around their sun or even other planets close
           | to them? If it's their star is gonna blow why would they go
           | any further than the nearest star?
        
             | signal11 wrote:
             | Depends on the ELE. There are several which can swallow
             | entire solar systems, and the nearby stars may not be
             | hospitable. Maybe the endgame is to find a habitable
             | planet?
        
         | Cthulhu_ wrote:
         | It wouldn't even be about colonization, because it would be
         | infeasible to make a return trip or, unless communications
         | technology changes (e.g. quantum entanglement magic), even
         | phone home upon arrival. The only thing I can think of is
         | survival of the species, survival and spread of life itself.
         | It's not infeasible to believe that's how life on earth started
         | - not as a spontaneous process, but a natural spread of life
         | from elsewhere (panspermia) or a previous life form spreading
         | the building blocks on purpose.
         | 
         | But life on earth has been going on for hundreds of millions of
         | years so I don't think we'd find any traces of it.
        
           | edgyquant wrote:
           | Life on Earth is billions of years old.
           | 
           | https://en.wikipedia.org/wiki/Timeline_of_the_evolutionary_h.
           | ..
        
         | Aeolun wrote:
         | > Who would want to make the trip, and condemn thousands of
         | generations of her progeny
         | 
         | Presumably the people that do this do not think ship life will
         | be _that_ bizarre.
         | 
         | I'm frankly more concerned about the sustainability aspect than
         | how daily life will work.
        
       | PaulHoule wrote:
       | Their propulsion speeds are low (today's technology but you'd
       | need D-D fusion or antimatter to keep warm) but 100 Myear
       | survival time is hard to believe.
       | 
       | I also don't believe a species that masters slow interstellar
       | travel would care about stars and planets. Most of the mass which
       | could be exploited by life is floating between the stars in the
       | form of comets and if you could "live off the land" out there you
       | could create millions of miles of apartment buildings and
       | shopping malls.
       | 
       | Why trek into an inner solar system and build yourself a space
       | shuttle that can land full of fuel and then take off when you are
       | settled into a space lifestyle?
        
         | shakezula wrote:
         | > I also don't believe a species that masters slow interstellar
         | travel would care about stars and planets.
         | 
         | > Why trek into an inner solar system
         | 
         | Why venture off to unknown shores to build yourself a farm when
         | you're settled into a comfy European lifestyle?
         | 
         | Although we only have ourselves as a data point, I think that
         | natural curiosity is a strong evolutionary trait that we
         | developed, and it's not a huge stretch to assume that other
         | lifeforms would develop the same curiosity.
        
           | throwaway316943 wrote:
           | I imagine an interstellar civilization would have this to say
           | about planets:
           | 
           | "A nice place to visit, but you wouldn't want to live there"
        
       | fnord77 wrote:
       | so, in 13.51 billion years, where are they?
        
         | ceejayoz wrote:
         | https://en.wikipedia.org/wiki/Fermi_paradox#Hypothetical_exp...
        
       | aaroninsf wrote:
       | ITT: many propositions and counter-propositions constrained by
       | presumptions that next-level civilization and its modes of being
       | and interacting with the universe are "necessarily" much like our
       | own.
       | 
       | One example: "upload" and "simulation" do not have _any_
       | predetermined relationship to the material behavior of a species
       | engaged in it. The mapping between agency in any presented
       | reality and the species-consensual one is _arbitrary_ and the
       | distinction between simulation and reality might just as well be
       | framed as a question of sensorium cum UX.
       | 
       | Very very little can be extrapolated upward from our own
       | limitations and constitution either as individuals or societies
       | or species.
       | 
       | An even deeper example: fundamentals like the relationship to
       | time may be radically different. It may not just scale, it may be
       | fractal; and the notion of what constitutes agency and the locus
       | of selfhood and identity, and hence self-interest, may be
       | distributed emergent and predicated on an interplay between ant-
       | and-colony at multiple levels, each of which is fully "conscious"
       | and intentional in the sense we understand those things, at
       | different time scales.
       | 
       | What does a third grader know of amortization?
       | 
       | We are not even out of the womb as a species.
        
       | tomiplaz wrote:
       | There's a great video on this topic from the Cool Worlds Lab
       | channel: https://www.youtube.com/watch?v=c7OeeGcMFMc
       | 
       | Taking into account ship ranges and settlement lifetimes produces
       | very different results (15:36 in the video).
        
       | carapace wrote:
       | Two things: 1) Check out "The Millennial Project":
       | 
       | https://en.wikipedia.org/wiki/The_Millennial_Project:_Coloni...
       | 
       | > The Millennial Project: Colonizing the Galaxy in Eight Easy
       | Steps by Marshall T. Savage is a book (published in 1992 and
       | reprinted in 1994 with an introduction by Arthur C. Clarke) in
       | the field of exploratory engineering that gives a series of
       | concrete stages the author believes will lead to interstellar
       | colonization. Many specific scientific and engineering details
       | are presented, as are numerous issues involved in space
       | colonization.
       | 
       | I find the cover image of a green galaxy is very inspiring!
       | 
       | 2) Due to the nature of exponential growth, we will eventually
       | feel a population crunch when reproduction overwhelms the rate of
       | expansion. This is true even if we invent FTL ships. The crunch
       | would be delayed (perhaps for millions or billions of years) but
       | it is inevitable.
        
       | gmuslera wrote:
       | It may be the Dunning-Kruger effect for civilizations. The ones
       | that didn't reach the stage of interstellar travel think that is
       | trivial to travel and settle in other star systems. But the more
       | advanced ones may have different ideas, or think that it is a
       | waste of time/resources compared with some more interesting
       | alternatives.
        
       | user-the-name wrote:
       | > Ships are launched no more frequently (from both the home
       | system and all settlements) than every 0.1 Myr -- every 100,000
       | years;
       | 
       | > Technology persists in a given settlement for 100 million years
       | before dying out;
       | 
       | Those are... uh, some kind of numbers. Really not sure _what_
       | they think they are simulating here, but it sure does not sound
       | like anything we 'd expect to happen in reality.
        
         | asdfasgasdgasdg wrote:
         | Maybe their birth rates are so close to the replacement rate
         | they don't feel an urgent need to spread out from a given star
         | system very quickly. Or maybe they have modified their
         | sensibilities to prefer fully exploiting an existing system
         | before moving on to a new one. But yeah these parameters do not
         | seem realistic.
        
           | user-the-name wrote:
           | 100 million years ago, _grass_ didn 't exist, let alone
           | technology.
        
         | Aeolun wrote:
         | Maybe they wanted to be conservative, because if they use the
         | actual numbers the galaxy would go red in just a few frames?
        
           | jaspax wrote:
           | More like they have a bizarre mix of numbers which are way
           | too large and those which are way too small. Technological
           | civilization lasting 100M years per planet? But those
           | civilizations only try to colonize once per 100K years? And,
           | at the same time, their colony ships take tens of thousands
           | of years to reach their destinations? I have a hard time
           | imagining ways in which all of those are true at once.
        
             | foerbert wrote:
             | I'm not sure why you see this as so bizarre. This seems
             | like a fairly conservative estimate across the board,
             | intended to be used to produce some kind of lower bound,
             | rather than be an expected case. This is a pretty common
             | and normal idea.
             | 
             | Is it that you think the technological civilization
             | duration is not conservative? Remember we're talking about
             | a civilization that can cross the galaxy here. They can
             | show up in a star system and throw habitats across any
             | planets, moons, or asteroids they find appealing. They can
             | also set up whatever number of space structures they want.
             | What exactly do you think is so likely to utterly
             | extinguish this species in every star system within 100M
             | years?
             | 
             | The long duration between colonization events is not only
             | highly conservative, it also functions here to allow any
             | particular civilization to be pretty irrelevant. Even if
             | some crazy war breaks out within a star system, a single
             | surviving habitat is enough to allow the next colonization
             | to still occur.
             | 
             | So, yeah? It all strikes me as a pretty normal conservative
             | estimate intended to let them figure out some kind of
             | reasonable lower bound here. All pretty normal stuff.
        
               | user-the-name wrote:
               | What is "conservative" about a civilisation lasting 100
               | million years? That is literally astronomical. That about
               | twice as long as grass has existed.
        
               | Aeolun wrote:
               | > Remember we're talking about a civilization that can
               | cross the galaxy here.
               | 
               | That would be earth at the current point in time. Given
               | 100k years I'm sure we could fabricate a huge colony
               | ship, and accelerate it to 10km/s. What we won't be able
               | to do is throw up habitats all over the solar system.
               | 
               | By that point all your tech is thousands of years old. It
               | seems unlikely it'd be capable of doing more than drop
               | you off on whatever planet you were aiming for (or keep
               | floating around, if it's a lifeless husk).
        
       | bamurphymac1 wrote:
       | Early bird gets the worm.
        
       | biggestlou wrote:
       | I'm still looking for intelligent life on _this_ planet!
        
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